Deng Yuanlei had actually been waiting for a while. He had already unsealed his acupoint by himself and wanted to launch a surprise attack on the Dragon King. But the other side had never gone near him. Instead, the Dragon King had sent Shangguan Ru to release the acupoint.
Deng Yuanlei didn't know that the Dragon King didn't know how to strike acupoints at all, not to mention unsealing them.
But he changed his mind at the last moment. Killing the little girl would not do him any good, but holding her hostage could potentially bring him a lot of benefits. She was obviously having an affair with the Dragon King.
Shangguan Ru was caught unprepared. Although she had grown up in the castle, she had never developed the deep-seated vigilance of a killer disciple. To her, the castle had always been warm and safe, and there had never been any need for her to worry about her life or safety.